Frangible projectile

ABSTRACT

A bullet assembly with a projectile body formed of a low mass frangible material lethal over a limited effective range and which may be provided with an obturator between the projectile body and a propellant charge.

10s Mei 1191 Zaid 1 Dec. 25, 1973 FRANGIBLE PROJECTILE 3.060.856 10/1962Dunn 102/41 3.137.195 6/1964 Rosenberg, Jr.... 102/95 X [75] InvenmnMelvm Old westbury, 3.326.133 6/1967 Sladlefet al 102/927 73 AssigneezCOWS Inc, Hartford Conn 463,528 11/1891 Mieg l 1. 102/41 3.062,l4511/1962 Morgan et a1. 1. 102/38 [22] Filed: Sept. 27, 1971 [21] Appl.No.2 183,967 Primary Examiner-Robert F. Stahl Attorney-Prutzman, Hayes,Kalb & Chilton [52] US. Cl. 102/41, 102/927 [51] Int. Cl. F42b 5/22,F42b 11/38 [57] ABSTRACT [58] Field of Search l02/921.(7):2/49l3, 3985,A bullet assembly with a projectile y formed of a low mass frangilbematerial lethal over a limited effec- [56] References Cited tive rangeand which may be provided with an obturath t'l b d d 11 t UNTED STATESPATENTS grarlgazlween e PIOJEC 1e 0 y an a prope an 3.598.058 8/1971Smith 102/41 3,650,213 3/1972 Abbott et al 102/92.7 10 Claims, 5 DrawingFigures if M PATENIEDUEEZSIBH 3,780, 657

sum 1 or 2 FIG. 3 w w INVENTOR MELVIN ZAID ATTORNEYS FRANGIBLEPROJECTKLE This invention generally relates to limited lethalityammunition and particularly concerns frangible projectiles.

Known frangible projectiles have heretofore been directed to types usedfor practice purposes, which would normally break up immediately afterleaving the muzzle, or those types used in target or shooting galleries,which disintegrate harmlessly upon target impact. Recent efforts havebeen directed to providing a different type ammunition having aprojectile fully lethal for a limited range. Experimentation withfrangible bullets utilizing a variety of materials and powder chargesover different ranges has resulted in a continuing effort to providesatisfactory projectile frangibility while also establishing a limitedeffective range throughout which the projectile is lethal for specificapplications, for example, riot control and similar purposes such asantihijacking. Such applications require significant damage to livetargets and subsequent breakup into harmless pieces after impact withand penetration of the projectile into the target while additionallyrequiring that the projectile be non-lethal beyond a specified range foruse in close quarters, such as in aircraft.

Accordingly, a primary object of this invention is to provide a new andimproved projectile which will serve seemingly incompatible objectivesof being fully lethal over an established limited effective range andalso break-up upon impact to minimize any second target damage.

Another object of this invention is to provide a frangible projectile ofthe above-described type particularly suited for low cost manufacture.

A further object of this invention is to provide an improved frangiblebullet assembly particularly suited for use in different types ofprojectile containers such as a standard cartridge case or a disposablerevolver cylinder. Included in this object is the aim of providing sucha bullet assembly having a novel obturator for effecting spin velocityto the projectile mass and also affording it shock relief when fired.

Other objects will be in part obvious and in part pointed out in moredetail hereinafter.

A better understanding of the objects, advantages, features, propertiesand relationships of the invention will be obtained from the followingdetailed description and accompanying drawings which set forth certainillustrative embodiments and are indicative of the various ways in whichthe principle of the invention is employed.

In the drawings:

FIG. 1 is a schematic view of a gun barrel and firing mechanism suitablefor use with this invention;

FIG. 2 is a longitudinal side view, partly broken away and partly insection, showing one embodiment of a limited lethality projectile withina standard cartridge case;

FIG. 3 is a fragmentary longitudinal cross sectional view, partly brokenaway, of another embodiment of a limited lethality projectile within adisposable revolver cylinder;

FIG. 4 is a graph showing a muzzle velocity band and range relationshipsfor a projectile of this invention; and

FIG. 5 is a graph showing muzzle velocity and lethal range relationshipsfor a projectile of this invention.

Referring to the drawings in detail, a conventional cartridge case 10,e.g., a 0.38 caliber cartridge case fabricated from suitable materialsuch as brass is shown in FIG. 2 with a projectile l2 fitted within anopen end of the cartridge case 10. A propellant or powder chamber 14,located rearwardly of the projectile l2 and forwardly ofa closed rearend 16 of the cartridge case 10, is partially filled with a conventionalpropellant 18. A primer 20 is centrally located in a rear face of theclosed rear end 16 of the cartridge case 10. The primer 20 may be astandard percussion sensitive type which detonates upon being struck bya firing pin, such as at 22 of a revolver 24 illustrated in FIG. 1, andshock wave and flame exits through a passageway 26 to ignite thepropellant 18 and cause substantially instantaneous expansion of thebyproducts of combustion to expel the projectile 12 from a barrel 28 ofthe revolver 24.

A typical 0.38 caliber projectile such as a standard lead bulletpossesses a muzzle velocity of about 850 feet per second and will havean effective standard projectile range of approximately 1,200 feet.While the actual range is greater than 1,200 feet, for purposes of thisdescription, that range wherein there is lethal stopping or hittingpower is considered to be the effective range.

To obtain lethal hitting power over a limited effective range inaccordance with this invention, the projectile 12 comprises a bodyformed of a solid nonmetallic frangible material which fragmentizes uponimpact and which has a low mass density relative to that of a standardlead bullet, to desirably limit the range of the projectile 12 to afirst distance of travel which is well short of the normal range of astandard lead bullet fired at the same muzzle velocity. Morespecifically, the material of the projectile 12 is a cementitiousmaterial of substantially uniform density throughout the projectilemass, and the propellant 18 selected is one which would have sufficientforce to impart at least lethal velocity over a preselected range whichis herein referred to as a first distance of travel. That is, should theprojectile l2 strike a kidney, heart or other major organ of an animalbody over such first distance, the impact would be fatal to the animal.Such results are virtually ensured by the frangibility characteristicsof the projectile 12. The frangibility of the projectile 2 is chosen toeffect a wound cavity of significantly amplified size relative to thesize of the projectile body before fragmentation, and fragmentationeffects an invaluable advantage in minimizing second target damage whenused, for example, in riot control. Fragmentation to a powdery substanceupon target impact is not sought, although this result may well occurupon impact of the projectile 12 with a hard metal surface such as sheetaluminum, for example, within the confines of an aircraft. Rather, thetype of fragmentation sought is that which throughout a predeterminedlimited lethal range (or first distance of travel) will result inbreak-up of the projectile body upon impact with endoskeletal animalflesh. A broad spectrum of different lethality levels at preselectedmuzzle velocities and strike distances has been found by testing variousfrangible projectiles formed by the mixing of different cementitiousmaterials. Experimentation has also been conducted under similarcontrolled conditions with weapons having both smooth bore and rifledbarrels. Based on such experiments, it is believed that the lethalitylevel is significantly higher when a spin velocity is imparted to thefrangible projectile 12.

To provide such projectile spin, a barrier means or obturating wad 30 islocated within the case between the propellant 18 and the projectilebody 12 to distribute propelling forces over the entire rear face of theprojectile body 12 while preserving its integrity upon being fired froma gun, in addition to imparting desired spin velocity to the projectilebody 12. In the specifically illustrated embodiment of this inventionshown in FIG. 2, the wad 30 is preferably a sleeve formed of suitableplastic material and having an interior dividing wall 32 located midwaybetween opposite open ends of the sleeve providing a pair of cup-shapedend portions facing in opposite axial directions. The forwardly facingcup-shaped end portion receives a correspondingly shaped reduced rearend portion 34 of the projectile body. The cup-shaped rear end portionof the wad 30 is accordingly formed with a recess 36 facing the powderchamber 14 with a circumferentially extending wall 38 surrounding therecess. The wall 38 is deformable radially outwardly upon ignition ofthe propellant 18 in the powder chamber 14 thereby to engage riflinglands such as at 40 within the gun barrel 28 for imparting the desiredspin velocity to the frangible projectile 12.

Cementitious material generally includes any substance for making bodiesadhere to each other such as asphalt, glue, gypsum, lime, paste, plasterof Paris, Portland cement, tar and similar substances. Specificcompositions of the frangible projectile bodies of this invention havebeen made of cement and plaster.

Cement is basically a finely powdered mixture oflime and earth clay orimpure calcium aluminum silicate. Portland cement is composed of acomplex calcium aluminum silicate. As with plaster, additives can beintroduced into the mix, such as gypsum to retard setting, andaggregates may be added for strength and economy. Typical aggregatesvarying in size include crushed marble, white quartz, granite, gravel,marble dust, silica flour, fine sand, and talc.

The parent mineral of plaster is gypsum which is found in several forms:alabaster (a massive variety of gypsum), white spar or satin spar (afibrous variety of gypsum), selenite (a crystalline form of themineral). Gypsum is occasionally referred to as hydrated sulphate oflime, hydrated calcium sulphate and, chemically, CaSO -2H O. Plaster isalso known as CaSO 1/2H O, sulphate of lime, hemihydrate of calciumsulphate, castin gp last er, gypsum plaster, and dental plaster, inaddition to specific trade names.

Generic names of plaster are alpha gypsum plaster, alpha hemihydrate ofcalcium sulphate, beta hemihydrate of calcium sulphate. The alph andbeta are different crystalline structures; the alpha hemihydrate ofcalcium sulphate being sold under the trademark Hydro' cal," and thebeta hemihydrate of calcium sulphate being normal plaster. The alphaversion can be made more dense; thereby demanding less water.

Numerous commercially available additives (up to 42 according to onemanufacturer) may be included in the plaster mix with each additiveproviding some control on expansion, set, strength, flow, water use,etc. These additives include sulphates as accelerators; commercialretarding agents such as borax, carpenters glue, calcined lime, powderedmarshmallow roots, alcohol, sugar and citric or acetic acid; hardenerssuch as lime, magnesium fluosilicate, white dextrine or gum arabic, andwhite Portland cement; binding materials such as long and short-fibered.asbestos, ordinary white absorbent cotton, sisel or hemp, and animalhair. Specific proportions of each additive is normally treated asproprietary information by each manufacturer.

In different plaster mixtures, different levels of lethality have beenobtained. Two specific examples, which perhaps may be preferred, aremixtures of water with the previously mentioned Hydrocal plaster and aplaster of Paris sold under the trademark Red-Top.

For example, a total 18 grain mixture, 67 percent Red-Top plaster ofParis and 33 percent water by weight, was mixed for 15 to 20 secondsafter adding the plaster to the water in a plastic beaker. The mix wasthen poured into molds (not shown) each of which contained a plastic wad30. After being leveled off, the molds were cured in a 60 C. oven fortwo hours. The projectiles were then ejected from the molds and insertedinto standard 0.38 caliber cartridge cases, such as at 10, loaded withthree grains of propellant sold under the trademark Bullseye. The volumeof each cartridge case after insertion of a plaster round and wad was0.028 cubic inches giving a loading density of 0.015 pound per cubicinch in all cases.

The same procedure was utilized in making Hydrocal plaster bulletassemblies except that a 19 grain mixture of 67 percent Hydrocal-plasterand 33 percentwater was used.

In actual tests utilizing a 0.38 caliber revolver having a two inchrifled barrel, an average strike velocity of about 900 and 1,100 feetper second was obtained respectively at ranges of about 8 feet and 4feet from muzzle to target. The Red-Top bullet assembly resulted inlarge volume muscle wounds although no significant residual velocity ofthe projectile was observed after bone impact. While it appeared fromsuch tests that the Red-Top bullet assembly can destroy ribs andmuscles, the bullet assembly did not appear to have sufficientpenetrating capability to affect internal organs after penetratingclothing and breaking bone. At the tested ranges and strike velocities,no penetration of 40 mil thickness aluminum sheet occurred.

A 19 grain Hydrocal plaster projectile provided full penetration of 40mil aluminum sheet at a strike velocity of approximately 1,200 feet persecond at about 4 foot range and less. This projectile also fullypenetrated bone with sufficient velocity to inflict mortal damage onmajor organs and blood vessels over a short range of 6-8 feet withstrike velocities of about 1,000 fps while being nonlethal beyond about10 feet. When striking an array of 1 inch pine boards at a short rangeof about 6 to 8 feet away in which the boards were separated by airspace, 'only the first board was penetrated by the Hydrocal rounds, andthe second board received only plaster dust and sustained no damage.These characteristics exhibited by Hydrocal" rounds should prove to beexceedingly valuable when double plexiglas aircraft cabin windows andhardboard-backed aluminum sheet is struck by such a frangibleprojectile.

All Red-Top and Hydrocal projectiles were found to have penetratedtissue without exiting and to have opened up a wound cavity many timesthe size of the projectile body. Each projectile upon recovery was alsofound to be broken into one-fourth inch and smaller diameter pieces. Itis believed that the effect of the projectile pieces traveling outwardlyfrom the wound tract due to spin velocity accounts for the increasedwound volume of the projectiles, and this concept appears to besubstantiated by a slightly reduced wound volume found for more cohesiveI-Iydrocal plaster mix. It was also noted that nondeformable metallicprojectiles, such as aluminum having the same mass as the plasterprojectiles, do not break up when fired at the same muzzle velocitiesand did virtually no tissue damage. Aluminum projectiles, of twice themass of the frangible projectiles, yield wounds of low volume similar tothose inflicted by standard lead bullets.

'The relatively low mass density of the projectile l2 and its cohesivestrength are preselected to ensure that upon impact and penetration ofendoskeletal animal flesh over the first lethal distance of travel ofthe projectile, the projectile 112 will possess a sufficiently highvelocity to effect a lethal striking velocity despite the high velocitydrop-off due to the low mass of the projectile 12 and the highfrictional atmospheric drag imparted thereon before impact.

Velocity drop-off with range of the described Red- Top'bullet assemblyis presented in FIG. 4! for a selected muzzle velocity band. Muzzlevelocity can be increased by changing the propellant mix, the quantityof the propellant and/or the barrel length. While the subject oflethality is not subject to precise definition, nonetheless, to evaluatelethal range of a selected muzzle velocity, the muzzle velocity requiredat any specific range is calculated to obtain the lethal strikingvelocity and the propellant loading is adjusted to obtain such muzzlevelocity. Any lethality effects due to change in mass have to beevaluated experimentally since standard lethality tables do not exist atthis time for frangible projectiles or for additives to the cementitiousmix. The above described Red-Top plaster rounds appear lethal for strikevelocities greater than about 700 feet per second. superimposing thisapproximate lethal limit onto FIG. 4, lethal and nonlethal ranges forthis band of muzzle velocities are defined. The lethal range" versusmuzzle velocity for Red- Top plaster rounds can be obtained directlyfrom FIG. 4 and the results are presented in FIG. 5 which is a graphshowing typical muzzle velocity and lethal range relationships for sucha Red-Top plaster projectile.

To further increase the lethality of the round, muzzle velocity may beincreased, weight increasing additives such as shot and similarsubstances may be included that can be held together in a plastermatrix, and/or the projectile mass density may be increased.

The utilization of the inventive concept of this invention, whileideally suited for incorporation into standard cartridge cases, isadditionally useful in other applications. For example, a disposablecylinder is shown in FIG. 3 ofa type fully described in my US. Pat.application Ser. No. 104,603 entitled Improved Cylinder for Revolversfiled Jan. 7, 1971, assigned to the assignee of this invention, thesubject matter of this application being incorporated herein byreference. In FIG. 3 the same numbers as in FIG. 2, increased by 100,are used to identify like parts. The modified form of the inventionillustrated in FIG. 3 shows a projectile body 112 provided in adisposable cylinder 140 to be fired from a suitable weapon such as therevolver 24. The loading of the projectile 1 12 is substantiallyidentical to that previously described in connection with the projectilel2 fitted in the standard cartridge case 10. After being loaded into thedisposable cylinder 140, each round M2 is preferably sealed with aprotective coating 142 which may be a brushable one part, thixotropiccompound which air dries to a tough, rubbery protective film.

A frangible projectile constructed in accordance with this inventionwill provide a limited lethality range for a selected band of muzzlevelocities and is desirably non-lethal beyond such a range to meet needsfor such ammunition in close quarters for effecting significant damagewhile retaining frangibility. In addition, the projectiles of thisinvention are particularly useful in connection with both a standardcartridge case and a disposable cylinder and in either event may bequickly and easily mass produced at low cost.

As will be apparent to persons skiiled in the art, variousmodifications, adaptations and variations of the foregoing specificdisclosure can be made without departing from the teachings of thepresent invention.

I claim:

I. A bullet assembly suitable for being propelled from a gun barrelhaving rifling lands and grooves formed therein and comprising aprojectile, a container, a propellant received in the container andhaving sufficient force to impart at least a lethal striking velocity tothe projectile over a first distance of travel, and an obturating waddisposed between the propellant and the projectile with the wad engaginga trailing end portion of the projectile, the obturating wad beingengageable with the rifling lands to impart a spin velocity to theprojectile upon its being fired from the gun and additionally effectingcombustion gas sealing within the barrel during exit of the projectiletherefrom, the projectile being formed ofa solid nonmetalliccementitious material which is fragmentizable and of low mass density,relative to a standard metallic projectile, the projectile mass havingsubstantial uniformity throughout and being of sufficiently low massdensity to limit travel of the projectile to a total distance of travelgreater than said first lethal distance of travel but less than apredetermined standard projectile range of a standard metallicprojectile fired from a gun at the same muzzle velocity.

2. The bullet assembly of claim I wherein the container is a standardcartridge case with the projectile received at least in part within thecase.

3. The bullet assembly of claim 1 wherein the obturating wad distributesthe propelling forces over a rear face of the projectile.

4. The bullet assembly of claim 1 wherein the projectile is a solidhomogeneous mass.

5. The bullet assembly of claim 1 wherein the barrier means comprises anobturating wad fixed to said one of the projectile on a trailing endportion thereof.

6. The bullet assembly of claim 1 wherein the obturating wad is fixed toa trailing end portion of the projectile.

7. The bullet assembly of claim I further including protective sealingmeans covering exposed portions of the projectile.

8. The bullet assembly of claim 1 wherein the solid material of theprojectile is of a mass density and cohesive strength sufficiently lowto fragmentize upon impact without penetration of 40 mil thicknessaluminum sheet at a distance of ten feet and beyond.

9. The bullet assembly of claim 1 wherein the mass density and cohesivestrength of the projectile is sufficiently high to penetrateendoskeletal animal flesh over 8 ing radially outwardly deformable wallcooperating with the rearward end of the cartridge case to define achamber therein receiving the propellant, the radially outwardlydeformable wall of the obturating wad providing gas sealing of theproducts of combustion upon ignition of the propellant in addition topreserving the integrity of the projectile upon its being fired from thegun.

1. A bullet assembly suitable for being propelled from a gun barrelhaving rifling lands and grooves formed therein and comprising aprojectile, a container, a propellant received in the container andhaving sufficient force to impart at least a lethal striking velocity tothe projectilE over a first distance of travel, and an obturating waddisposed between the propellant and the projectile with the wad engaginga trailing end portion of the projectile, the obturating wad beingengageable with the rifling lands to impart a spin velocity to theprojectile upon its being fired from the gun and additionally effectingcombustion gas sealing within the barrel during exit of the projectiletherefrom, the projectile being formed of a solid nonmetalliccementitious material which is fragmentizable and of low mass density,relative to a standard metallic projectile, the projectile mass havingsubstantial uniformity throughout and being of sufficiently low massdensity to limit travel of the projectile to a total distance of travelgreater than said first lethal distance of travel but less than apredetermined standard projectile range of a standard metallicprojectile fired from a gun at the same muzzle velocity.
 2. The bulletassembly of claim 1 wherein the container is a standard cartridge casewith the projectile received at least in part within the case.
 3. Thebullet assembly of claim 1 wherein the obturating wad distributes thepropelling forces over a rear face of the projectile.
 4. The bulletassembly of claim 1 wherein the projectile is a solid homogeneous mass.5. The bullet assembly of claim 1 wherein the barrier means comprises anobturating wad fixed to said one of the projectile on a trailing endportion thereof.
 6. The bullet assembly of claim 1 wherein theobturating wad is fixed to a trailing end portion of the projectile. 7.The bullet assembly of claim 1 further including protective sealingmeans covering exposed portions of the projectile.
 8. The bulletassembly of claim 1 wherein the solid material of the projectile is of amass density and cohesive strength sufficiently low to fragmentize uponimpact without penetration of 40 mil thickness aluminum sheet at adistance of ten feet and beyond.
 9. The bullet assembly of claim 1wherein the mass density and cohesive strength of the projectile issufficiently high to penetrate endoskeletal animal flesh over said firstdistance of travel while yet being fragmentizable upon entry therein.10. The bullet assembly of claim 1 wherein the container includes agenerally tubular cartridge case closed at a rearward end thereof, theprojectile being of a generally cylindrical shape received in thecartridge case and closing an open forward end thereof, and wherein thebarrier means includes an obturating wad fixed on a trailing end portionof the projectile, the obturating wad having a rearwardly facing recessand a surrounding radially outwardly deformable wall cooperating withthe rearward end of the cartridge case to define a chamber thereinreceiving the propellant, the radially outwardly deformable wall of theobturating wad providing gas sealing of the products of combustion uponignition of the propellant in addition to preserving the integrity ofthe projectile upon its being fired from the gun.